The increasing demand for clinical-chemical and immunological analyses has led to the progressive miniaturization of research and investigation processes. As a result, labour time, space, material and reagents are saved. Most analyses are performed with vessels which limit the reaction mixture in five directions, namely to four sides and to the bottom. The space and material requirements could be further reduced by a support bounding the reaction mixture in only one or two directions. For example, in the case of blood group determinations, the reactions can take place on slides, this also applying to immunofluorescent assays on frozen sections (cf H. P. Seelig, H. P. Geisen and R. Seelig in Lab. med. 2, 1978, pp. 133-139). If, outside the reaction fields, the slides are covered with an inert, water-repellent layer, the various specimens which are on the slide at the same time cannot mix together as easily (cf P. O'Neill and G. D. Johnson in Ann. N. Y. Acad. Sci. 177, 1971, pp. 446-452; coating with polytetrafluoroethylene). In this process, the drops easily dry on the surface, even if the slides are in a moist chamber. This leads to spoiling or to a falsification of the analysis through the concentration of the dissolved substances rising. Thus, the technique recommended by Tung is frequently used (cf K. S. K. Tung in J. Immunol, Methods 18, 1977,pp. 391-392). According to this technique, a further uncoated slide is placed with a gap over the first slide in such a way that it is in contact with the underlying drops. However, the various specimens then often run together and mix. The specimens particularly tend to mix if a condensation water film has formed on the upper slide or if the two slides have not been accurately superimposed or if the upper slide with respect to the other, as well as when the drops have not been accurately positioned. The drops must therefore be kept a considerable distance from one another to prevent their running together. This is contrary to a reduction in size of the analytical apparatus. In addition, in this form, it is very difficult to automate the process. The reactions also last a relatively long time, because mixing within the drops must take place manually and individually in succession. For this purpose, a stirring rod is required for each drop, because mixing by tilting the slide is not very effective.
Austrian Pat. No. 170,898 (Inventor: Dr. F. Mandula) published on Apr. 10th, 1951 already discloses an apparatus for serological research in which a plurality of cup-shaped depressions are provided in a base plate. These depressions are filled with the substance under investigation. The depressions are then covered with a thin plate. The covered plate is placed in a vibrating apparatus where the substances placed in the cup-shaped depression are mixed by the vibrating movements.
DE-OS No. 2,527,770 (Inventors: Berndt and Timmermann), published on Jan. 13th, 1977 discloses a slide for performing agglutination reactions having a support plate with reaction fields arranged in grating or grid-like manner. The reaction fields are formed by individual mirrors, preferably having a planar reaction surface, whilst between the reaction fields, the area surrounding the mirrors is opaque or transparent and is also glare-free.
East German Pat. No. 96,784 (Inventors: Thielmann and Horn), published on Aug. 5th, 1976 discloses a process and an apparatus for measuring enzyme activities and substrate or cosubstrate concentrations in the ultramicro-range in which two superimposable plates made from a hard material, preferably plastic, are provided with chambers, preferably in the form of countersinks, surrounded by annular recesses which form reaction chambers on superimposing and clamping together the plates.
U.S. Pat. No. 3,783,105 (Moyer et al), patented on Jan. 1st, 1974 discloses an apparatus and a process for the quantified indication of the activities on a large number of enzymes present in biological fluids. For this purpose, microporous membranes are used as filters.
Finally, East German Pat. No. 107,783 (Inventor: Horn et al), published on Aug. 12th, 1974 discloses a specimen carrier for performing chemical analyses in the ultramicro range comprising two substantially planar plates which, at least on their facing surfaces have interengaging depressions and/or projections.
The object of the invention is to provide an analytical apparatus requiring only two limiting surfaces for each analysis.
Another object of the invention is to provide apparatus which permits examination of a large number of specimens simultaneously, while taking up the minimum amount of space and while preventing the specimens from mixing together. This leads to savings in labour time, material and reagents.
Another object of the invention is to provide apparatus which keeps the reaction times short for the rapid performance of the process.
A further object of the invention is to provide apparatus which can also be used outside a damp chamber.
Yet another object of the invention is to provide apparatus which is automated to the greatest possible extent while maintaining its suitability for use in many branches of biochemistry and clinical chemistry.